(a) Field of the Invention
The present invention relates to liquid crystal displays (LCDs) and more particularly to a system and method for efficiently manufacturing LCDs in an automated environment.
(b) Description of Related Art
Liquid crystal displays (LCDs) are widely known and are used in a variety of display environments. An LCD is typically constructed with two panels having field-generating electrodes on interior facing surfaces separated by a generally uniform gap between the panels where the gap is filled by a liquid crystal (LC) layer. The LCD displays images by selectively applying voltages to the field-generating electrodes to generate an electric field in the LC layer. This electric field determines the orientation of LC molecules in the LC layer in order to adjust the polarization of incident light upon the LCD.
Traditionally, the LCD includes a plurality of pixels arranged in an array formation along with a plurality of electrical signal lines for conducting the electric voltage and driving the pixels. For example, these signal lines can be gate lines for transmitting scanning signals or data lines for transmitting data signals. Each pixel typically includes a pixel electrode and a storage electrode. The pixel electrode can be a thin film transistor (TFT) connected between the gate lines and the data lines in order to control the data signals. The storage electrode and the pixel electrode form a storage capacitor for the pixel in order to preserve the data signals for a predetermined amount of time allowing the image on the LCD to remain stable for viewing by an observer.
A liquid crystal (LC) display typically comprises an LC display panel assembly formed by two display panels upon which field generating electrodes are formed, and having an LC layer located in between the two display panels. LC molecules in the LC layer are rearranged by the electric field generated by applying voltages to the electrodes. Accordingly, the transmittance of light passing through the LC layer is controlled by the rearrangement of the LC layer. The LC display panel assembly further includes a plurality of signal lines for transmitting the voltages to the LC display panel assembly and the field generating electrodes.
A driving circuit connected to the signal lines supplies the control voltages to generate the electric fields that rearrange the molecules of the LC layer. The driving circuit can be a single integrated circuit (IC) chip, or can be a part of a larger electronic circuit. The driving IC chip can be affixed to a flexible printed circuit (FPC) film and electrically connected to the LCD by a plurality of conductive lead lines carried on an insulation film, such as a polyimide film. A FPC film carrying an IC chip is generally referred to as a tape carrier package (TCP) where the IC chip is affixed to the FPC film by a tape automated bonding (TAB) process. The bonded IC chip is electrically connected to the signal lines of the LC display panel assembly through the lead lines of the TCP.
As described, the lead lines of the TCP include a plurality of output side lead lines and a plurality of input side lead lines that are connected, respectively, to the output terminals and input terminals of the IC chip. The signal lines of the LC display panel assembly include a plurality of connecting pads, or bonding pads, formed on edges of the LC display panel assembly. The output side lead lines of the TCP can be electrically connected to the connecting pads by a bonding device, for example, while the input side lead lines of the TCP can be soldered to a printed circuit board (PCB) in order to transmit the various control signals to the IC chip.
When the output side terminals of the TCP and the connecting pads of the LC display panel assembly are connected together, an anisotropic conductive film (ACF) is typically located in between. After the ACF is positioned between the output side terminals of the TCP and the connecting pads, the TCP is pressed to the connecting pads of the LC display panel assembly. However, since a first process for identifying the output side terminals of the TCP and a second process for pressing the connecting pads together are typically performed in sequence with the TCP at a single location prior to pressing, the total average cycle time (TACT) for this identifying and pressing may be increased.
The discussion in this section is only intended to enhance the understanding of the present invention, and should not be considered as an admission concerning prior art.